150 
THE OCEAN WORLD. 
prodigious, of animals sucli as the crustaceans, worms, and small fishes. 
They are all marine, nearly all attached to the same spot for life, and 
they live in colonies. Some few are isolated and live hy themselves, 
either free or attached to the soil. They differ altogether from the 
animals belonging to the Alcyonaria by their disposal of, and mode of 
multiplying, tentacula. These appendages in the Zoardharia never 
present the bipmnate arrangement which is observable in the Alcy- 
onaria. They are habitually simple, and, if they present ramifications, 
these are only exceptional. In nearly every instance, the tentacles 
exist to the number of twelve, eighteen, twenty-four, and even larger 
numbers, which form a sort of concentric crown to the animal. 
Zoantha thalassanthos (Lesson), which has given its name to the 
group, consists of large turf-like tufts of coral attached to a rock. Its 
animalcules are packed closely together, and their expanded flower- 
like heads have a curious resemblance to a mass of flowers in full bloom. 
They are borne on bending root-like stems of pure white, interlacing 
one with the other, surmounted by a fusiform or spindle-shaped body, 
pediculate and swelling towards the middle, but truncate at the 
summit, of a reddish-brown colour, marked with longitudinal stripes 
more highly coloured; its consistence is firm and parchment-like. 
From the body issues a tube, narrow, muscular, contractile, and red in 
colour, terminating at the summit in eight elongated arms or tentacula, 
of a pure yellow, traversed by a nervure of the same colour. The 
edges of these arms are fringed with fine pinnae, parallel to each 
other, of a bright maroon colour, and resembling the barbs of a 
feather. According to Lesson, the arms of this Zoantha are kept un- 
ceasingly in motion, which produces in the water small oscillating 
currents, in the course of which the animalcules on which the polypi 
feed are precipitated into the stream leading to their mouths. 
The tendency to produce a calcareous polypier is a property almost 
universal with animals of this class. Zoologists are agreed in dividing 
them into three very distinct orders — namely, the Antipathidje, con- 
sisting of the genera Antipathe s, Cirripathes, and Seipathes, in 
which the polypier is of a horny consistence ; the M/ldbepokid.2e, in 
which the polypier is calcareous and stony ; finally, the Actinida:, 
which produce no polypiers. 
